Prognostic significance of the Fas-receptor/Fas-ligand system in cervical squamous cell carcinoma

Intrinsic and extrinsic pathways of apoptosis: Role in cancer development and prognosis

Apoptosis, also named programmed cell death, is a fundament process required for morphogenetic homeostasis during early development and in pathophysiological conditions. It is come into existence in 1972 by work of Kerr, Wyllie and Currie and later on investigated during the research on development of the C. elegans. Trigger by several stimuli, apoptosis is necessary during the embryonic development and aging as homeostatic mechanism to control the cell population and also play a key role as defense mechanism against the immune responses and elimination of damaged cells. Cancer, a genetic disease, is a growing burden on the health and economy of both developing and developed countries. Every year there is tremendously increasing in the number of new cancer cases and mortality rate. Although, there is a significant improvement have been made in biotechnological and bioinformatic fields however, the therapeutic advantages and cancer etiology is still under explored. Several studies determined the deregulation of different apoptotic components during the cancer development and progression. Apoptosis relies on activation of distinct signaling pathways that are often deregulated in cancer. Thus, exploring the single or more than one apoptotic component underlying their expression in carcinogenesis could help to track the disease progression. Current book chapter will provide the several evidences supporting the use of different apoptotic components as prognosis and prediction markers in various human cancer types.

Genetic susceptibility to cervical cancer: role of common polymorphisms in apoptosis-related genes

Cervical cancer is a common malignancy which poses a significant health burden among women, especially those living in the developing countries. Although human papillomavirus (HPV) infection has been unequivocally implicated in the etiopathogenesis of the cancer, it alone is not adequate to contribute to the malignant transformation of cervical cells. Most HPV infections regress spontaneously, and only a small proportion of women have persistent infections which eventually lead to malignancy. This suggests that interplays between HPV infection and other cofactors certainly exist during the process of cervical carcinogenesis, which synergistically contribute to the differential susceptibility of an individual to the malignancy. Undoubtedly, host genetic factors represent a major element involved in such a synergistic interaction, and accumulating evidence suggests that polymorphisms in apoptosis-related genes play an important role in the genetic susceptibility to cervical cancer. This review consolidates the recent literatures on the role of common polymorphisms in apoptosis-related genes in genetic susceptibility to cervical cancer.

The role of CD95 and CD95 ligand in cancer

CD95 (Fas/APO-1) and its ligand, CD95L, have long been viewed as a death receptor/death ligand system that mediates apoptosis induction to maintain immune homeostasis. In addition, these molecules are important in the immune elimination of virus-infected cells and cancer cells. CD95L was, therefore, considered to be useful for cancer therapy. However, major side effects have precluded its systemic use. During the last 10 years, it has been recognized that CD95 and CD95L have multiple cancer-relevant nonapoptotic and tumor-promoting activities. CD95 and CD95L were discovered to be critical survival factors for cancer cells, and were found to protect and promote cancer stem cells. We now discuss five different ways in which inhibiting or eliminating CD95L, rather than augmenting, may be beneficial for cancer therapy alone or in combination with standard chemotherapy or immune therapy.

FAS-670 gene polymorphism and cervical carcinogenesis risk: A meta-analysis

FAS is a cell surface receptor that plays an important role in the etiology of cancer. Previous studies on the association between FAS-670 polymorphism and cervical carcinogenesis failed to reach a consensus; therefore, this meta-analysis was conducted to estimate the association of FAS-670 polymorphism and the risk of cervical cancer. This meta-analysis included 10 studies on FAS-670 genotyping, including a total of 2,901 cases and 2,831 controls. The complete overdominant model was applied in our meta-analysis [AB vs. AA: odds ratio (OR)=0.879, 95% confidence interval (CI): 0.775-0.998, P=0.046; BB vs. AA: OR=0.903, 95% CI: 0.775-1.052, P=0.190]. The random effects OR was 1.13 (95% CI: 0.95-1.34, I²=52.7%, P_{heterogeneity}=0.03). An ethnic subgroup analysis was subsequently performed. The OR for Asians was 1.25 (6 comparisons, 95% CI: 1.05-1.48, I²=23.5%, P_{heterogeneity}=0.03), whereas for Caucasians, no significant association was observed between FAS-670 polymorphism and cervical carcinogenesis (4 comparisons, OR=0.96, 95% CI: 0.75-1.24, I²=45.9%, P_{heterogeneity}=0.14).

FasL gene -844T/C mutation of esophageal cancer in South China and its clinical significance

In this study, we investigated the association between the FasL -844T/C polymorphism and the risk of developing esophageal squamous cell carcinoma (ESCC) in South China. For the investigation, we randomly selected 248 patients suffering from ESCC from Southern China along with 297 healthy individuals as the control group. The relationship between the FasL gene -844T/C SNP and ESCC was studied using PCR-RFLP and immunohistochemistry. The Fas -1377G/A SNP was also selected for investigation to detect whether it interferes with the functional effect of the FasL -844C/T polymorphism in ESCC development. A significant difference in the FasL -844T/C genotypes between the patients and the control group was observed (P<0.05), with those expressing the C allele having a significantly reduced risk of developing ESCC, however younger patients (<60 years) exhibited a more malignant pathological T grade if they were homozygous for the C allele. FasL -844 CC combined with the Fas -1377 G allele is a protective factor against ESCC. Having said this, even though the C allele has a protective effect prior to development of ESCC, once the host does develop the condition the tumour will develop faster and have a higher degree of malignancy than T carriers.

Lack of association between Fas rs180082 polymorphism and risk of cervical cancer: an update by meta-analysis

Background

The Fas rs180082 polymorphism has been reported to be associated with cervical cancer susceptibility, yet the results of these previous results have been inconsistent or controversial. The objective of this study was to explore whether the Fas rs180082 polymorphism confers susceptibility to cervical cancer.

Methods

The relevant studies were identified through a search of PubMed, Excerpta Medica Database (Embase), Elsevier Science Direct and Chinese Biomedical Literature Database (CBM) until July 2012. The association between the Fas rs180082 polymorphism and cervical cancer risk was assessed by odds ratios (ORs) together with their 95% confidence intervals (CIs).

Results

A total of 7 case–control studies were eventually identified. We found no association between Fas rs180082 polymorphism and cervical cancer susceptibility in overall population (G versus A: OR = 1.03, 95% CI = 0.99-1.07, P = 0.197; AG + GG versus AA: OR = 1.04, 95% CI = 0.98-1.09, P = 0.176; GG versus AA + AG: OR = 1.04, 95% CI = 0.84–1.31, P = 0.701). In subgroup analysis, similar results were found in Asian (G versus A: OR = 1.06, 95% CI = 0.97–1.15, P = 0.195; AG + GG versus AA: OR = 1.08, 95% CI = 0.98–1.19, P = 0.176; GG versus AA + AG: OR = 0.97, 95% CI = 0.51–1.84, P = 0.935) and African (G versus A: OR = 1.01, 95% CI = 0.97-1.15, P = 0.195; AG + GG versus AA: OR = 0.99, 95% CI = 0.91–1.07, P = 0.739; GG versus AA + AG: OR = 1.09, 95% CI = 0.94–1.25, P = 0.745).

Conclusion

This meta-analysis has shown that there is a lack of association of the Fas rs180082 polymorphisms with cervical cancer susceptibility. However, larger scale primary studies with the consideration of gene–gene and gene–environment interactions are still required to further evaluate the interaction of Fas rs180082 polymorphism with cervical cancer susceptibility.

Genetic polymorphisms as predictive and prognostic biomarkers in gynecological cancers: a systematic review

PURPOSE

Numerous studies have explored the potential role of genetic polymorphisms as predictive or prognostic biomarkers in gynecologic malignancies. A systematic review for all eligible polymorphisms has not yet been reported. The aim of this study was to summarize the current status of the field and provide direction for future research.

DESIGN

We searched literature databases (MEDLINE, EMBASE, Cochrane) from 2006 to April 2011 to identify studies evaluating the association between gene polymorphisms and clinical outcome in ovarian, endometrial, cervical, or vulvar cancer. The main outcome measures were overall survival (OS) and progression-free survival (PFS). Studies reporting relationships between polymorphisms and toxicity were also included.

RESULTS

Sixty two studies met the inclusion criteria. The median sample size was 140. Most of the included studies (n=50, 81%) were conducted in ovarian cancer patients. Almost a third assessed potential predictive associations between gene polymorphism and outcome in ovarian cancer. The most commonly evaluated genes were ERCC1, VEGF, ABCB1 (MDR), and GSTP1. Most studies (n=44, 71%) were observational case-series. Only four studies (6%) included a validation arm and patient population ethnicity was explicitly stated only in 27% of included studies.

CONCLUSION

No consistent association between any gene polymorphism and clinical outcome in gynecological cancers has been found across studies. There is incomplete adherence to the REMARK guidelines and inadequate methodology reporting in most studies. Moving forward, analysis of large trial-based clinical samples; adherence to the highest methodological standards, and focus on validation analyses are necessary to identify clinically useful pharmacogenomic biomarkers of outcome.

A common hereditary single-nucleotide polymorphism in the gene of FAS and colorectal cancer survival

Apoptosis plays an important role in embryogenesis, autoimmunity and tumourigenesis. Cell surface death receptors such as TNFRSF6 (FAS) confer a major apoptotic effect. A single-nucleotide polymorphism in the FAS promoter gene, −670A/G, modulates apoptotic signalling and has been related to susceptibility and progression of a variety of cancers. The present study aimed to evaluate the role of this polymorphism for survival of patients with colorectal cancer. We performed a retrospective analysis including 433 patients with histologically confirmed colorectal cancer. A Cox regression model including FAS -670 genotypes, age at diagnosis, tumour grading, primary tumour size, number of lymph nodes examined, number of metastatic lymph nodes, tumour stage and application of fluorouracil-based adjuvant chemotherapy was used to estimate the effect of the FAS genotype on survival. FAS −670A/G genotype frequencies were 24.2% (AA), 46.3% (AG) and 29.5% (GG). Forty-nine patients were excluded from the Cox regression analysis because of missing values. Out of the remaining 384 patients, 69 (18%) died during a follow-up of maximum 10 years. Mean follow-up time was 58 ± 34 months (median 55 months). Carriers of the homozygous FAS -670GG genotype had a significantly lower survival rate compared with AA/AG genotype carriers (relative risk 1.76, 95% confidence interval 1.08–2.87; P= 0.023). The FAS −670A/G polymorphism may be associated with overall survival time of patients with colorectal cancer.